arch/x86/kernel/olpc.c

   1 /*
   2  * Support for the OLPC DCON and OLPC EC access
   3  *
   4  * Copyright © 2006  Advanced Micro Devices, Inc.
   5  * Copyright © 2007-2008  Andres Salomon <dilinger@debian.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/delay.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/io.h>
  19 #include <linux/string.h>
  20
  21 #include <asm/geode.h>
  22 #include <asm/setup.h>
  23 #include <asm/olpc.h>
  24 #include <asm/olpc_ofw.h>
  25
  26 struct olpc_platform_t olpc_platform_info;
  27 EXPORT_SYMBOL_GPL(olpc_platform_info);
  28
  29 static DEFINE_SPINLOCK(ec_lock);
  30
  31 /* what the timeout *should* be (in ms) */
  32 #define EC_BASE_TIMEOUT 20
  33
  34 /* the timeout that bugs in the EC might force us to actually use */
  35 static int ec_timeout = EC_BASE_TIMEOUT;
  36
  37 static int __init olpc_ec_timeout_set(char *str)
  38 {
  39         if (get_option(&str, &ec_timeout) != 1) {
  40                 ec_timeout = EC_BASE_TIMEOUT;
  41                 printk(KERN_ERR "olpc-ec:  invalid argument to "
  42                                 "'olpc_ec_timeout=', ignoring!\n");
  43         }
  44         printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
  45                         ec_timeout);
  46         return 1;
  47 }
  48 __setup("olpc_ec_timeout=", olpc_ec_timeout_set);
  49
  50 /*
  51  * These {i,o}bf_status functions return whether the buffers are full or not.
  52  */
  53
  54 static inline unsigned int ibf_status(unsigned int port)
  55 {
  56         return !!(inb(port) & 0x02);
  57 }
  58
  59 static inline unsigned int obf_status(unsigned int port)
  60 {
  61         return inb(port) & 0x01;
  62 }
  63
  64 #define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
  65 static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
  66 {
  67         unsigned int timeo;
  68         int state = ibf_status(port);
  69
  70         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  71                 mdelay(1);
  72                 state = ibf_status(port);
  73         }
  74
  75         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  76                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  77                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
  78                                 line, ec_timeout - timeo);
  79         }
  80
  81         return !(state == desired);
  82 }
  83
  84 #define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
  85 static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
  86 {
  87         unsigned int timeo;
  88         int state = obf_status(port);
  89
  90         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  91                 mdelay(1);
  92                 state = obf_status(port);
  93         }
  94
  95         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  96                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  97                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
  98                                 line, ec_timeout - timeo);
  99         }
 100
 101         return !(state == desired);
 102 }
 103
 104 /*
 105  * This allows the kernel to run Embedded Controller commands.  The EC is
 106  * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
 107  * available EC commands are here:
 108  * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
 109  * OpenFirmware's source is available, the EC's is not.
 110  */
 111 int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 112                 unsigned char *outbuf,  size_t outlen)
 113 {
 114         unsigned long flags;
 115         int ret = -EIO;
 116         int i;
 117
 118         spin_lock_irqsave(&ec_lock, flags);
 119
 120         /* Clear OBF */
 121         for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
 122                 inb(0x68);
 123         if (i == 10) {
 124                 printk(KERN_ERR "olpc-ec:  timeout while attempting to "
 125                                 "clear OBF flag!\n");
 126                 goto err;
 127         }
 128
 129         if (wait_on_ibf(0x6c, 0)) {
 130                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
 131                                 "quiesce!\n");
 132                 goto err;
 133         }
 134
 135 restart:
 136         /*
 137          * Note that if we time out during any IBF checks, that's a failure;
 138          * we have to return.  There's no way for the kernel to clear that.
 139          *
 140          * If we time out during an OBF check, we can restart the command;
 141          * reissuing it will clear the OBF flag, and we should be alright.
 142          * The OBF flag will sometimes misbehave due to what we believe
 143          * is a hardware quirk..
 144          */
 145         pr_devel("olpc-ec:  running cmd 0x%x\n", cmd);
 146         outb(cmd, 0x6c);
 147
 148         if (wait_on_ibf(0x6c, 0)) {
 149                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
 150                                 "command!\n");
 151                 goto err;
 152         }
 153
 154         if (inbuf && inlen) {
 155                 /* write data to EC */
 156                 for (i = 0; i < inlen; i++) {
 157                         if (wait_on_ibf(0x6c, 0)) {
 158                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 159                                                 " EC accept data!\n");
 160                                 goto err;
 161                         }
 162                         pr_devel("olpc-ec:  sending cmd arg 0x%x\n", inbuf[i]);
 163                         outb(inbuf[i], 0x68);
 164                 }
 165         }
 166         if (outbuf && outlen) {
 167                 /* read data from EC */
 168                 for (i = 0; i < outlen; i++) {
 169                         if (wait_on_obf(0x6c, 1)) {
 170                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 171                                                 " EC to provide data!\n");
 172                                 goto restart;
 173                         }
 174                         outbuf[i] = inb(0x68);
 175                         pr_devel("olpc-ec:  received 0x%x\n", outbuf[i]);
 176                 }
 177         }
 178
 179         ret = 0;
 180 err:
 181         spin_unlock_irqrestore(&ec_lock, flags);
 182         return ret;
 183 }
 184 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 185
 186 #ifdef CONFIG_OLPC_OPENFIRMWARE
 187 static void __init platform_detect(void)
 188 {
 189         size_t propsize;
 190         __be32 rev;
 191         const void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
 192         void *res[] = { &propsize };
 193
 194         if (olpc_ofw("getprop", args, res) || propsize != 4) {
 195                 printk(KERN_ERR "ofw: getprop call failed!\n");
 196                 rev = cpu_to_be32(0);
 197         }
 198         olpc_platform_info.boardrev = be32_to_cpu(rev);
 199 }
 200 #else
 201 static void __init platform_detect(void)
 202 {
 203         /* stopgap until OFW support is added to the kernel */
 204         olpc_platform_info.boardrev = olpc_board(0xc2);
 205 }
 206 #endif
 207
 208 static int __init olpc_init(void)
 209 {
 210         unsigned char *romsig;
 211
 212         /* The ioremap check is dangerous; limit what we run it on */
 213         if (!is_geode() || cs5535_has_vsa2())
 214                 return 0;
 215
 216         spin_lock_init(&ec_lock);
 217
 218         romsig = ioremap(0xffffffc0, 16);
 219         if (!romsig)
 220                 return 0;
 221
 222         if (strncmp(romsig, "CL1   Q", 7))
 223                 goto unmap;
 224         if (strncmp(romsig+6, romsig+13, 3)) {
 225                 printk(KERN_INFO "OLPC BIOS signature looks invalid.  "
 226                                 "Assuming not OLPC\n");
 227                 goto unmap;
 228         }
 229
 230         printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
 231         olpc_platform_info.flags |= OLPC_F_PRESENT;
 232
 233         /* get the platform revision */
 234         platform_detect();
 235
 236         /* assume B1 and above models always have a DCON */
 237         if (olpc_board_at_least(olpc_board(0xb1)))
 238                 olpc_platform_info.flags |= OLPC_F_DCON;
 239
 240         /* get the EC revision */
 241         olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
 242                         (unsigned char *) &olpc_platform_info.ecver, 1);
 243
 244 #ifdef CONFIG_PCI_OLPC
 245         /* If the VSA exists let it emulate PCI, if not emulate in kernel */
 246         if (!cs5535_has_vsa2())
 247                 x86_init.pci.arch_init = pci_olpc_init;
 248 #endif
 249
 250         printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
 251                         ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
 252                         olpc_platform_info.boardrev >> 4,
 253                         olpc_platform_info.ecver);
 254
 255 unmap:
 256         iounmap(romsig);
 257         return 0;
 258 }
 259
 260 postcore_initcall(olpc_init);